Food allergies are caused by a reaction of the body's immune system to specific proteins in a food. In Canada, the most common foods that can cause allergic reactions are eggs, milk, mustard, peanuts, seafood (fish, shellfish, crustaceans), sesame, soy, tree nuts, and wheat.

Mediaplanet: How common are food allergies in Canada?

Julia Upton: Currently, more than 2.5 million Canadians are affected by food allergies. This often means one or more children in every classroom. Adjusting for nonresponse bias corrects overestimates of food allergy prevalence.

MP: How do you diagnose a food allergy in children?

JU: If you suspect that your child may be allergic to a food or has had an allergic reaction, it is important to see a doctor. An allergist can ask you about what happened and run some tests and tell you if your child is likely to have an allergy. There are a number of tests that can be used including a skin prick test and/or blood test. It’s important to note that these tests are not perfect and are much better at helping to find out who does not have an allergy than who does. Even people with no allergies can sometimes have positive tests so it is important that the testing is just one part of the diagnosis. To find out for sure if a child is allergic or not, it may be recommended to eat the food under the supervision of an allergist in a medical setting. A discussion with your allergist can determine which of these tests is right for your child.

For more information visit: Food Allergy Canada

MP: What are some common signs/symptoms of food allergy?

JU: Signs and symptoms of a severe allergic reaction can occur within minutes of exposure to an allergen. The ways these symptoms occur can vary from person to person and even from episode to episode in the same person.
Some common symptoms can include rash, swelling, redness, shortness of breath, chest pain or tightness. The most dangerous symptoms of an allergic reaction are trouble breathing and a drop in blood pressure.

For more information visit: Anaphylaxis in Schools & Other Settings

MP: How should an allergic reaction be treated?

JU: Epinephrine is the first line treatment for anaphylaxis. This life-saving medication helps to reverse the symptoms of a severe allergic reaction by opening the airways, improving blood pressure, and increasing the heart rate. It is recommended that epinephrine be given at the start of a known or suspected anaphylactic reaction.

MP: What safety precautions do you recommend for children living with food allergies?

JU: It’s important that children with food allergies know what they are allergic to, how to avoid it and always be prepared. Here are some helpful tips:

  • Carrying epinephrine (age appropriate)
  • Wearing MedicAlert® identification
  • Telling others (classmates, teachers)
  • Wash hands before and after eating
  • Eat only ‘approved’ foods from home/school
  • Avoid sharing food, straws, utensils and food containers with classmates.

MP: How can food allergies be prevented?

JU: It is not certain why children get food allergies. There is exciting new information that children at risk for peanut allergy who started eating peanut in infancy have less peanut allergies at age five years old than a child who was not exposed to peanut as a baby. This does not apply to children who already have a peanut allergy; if an allergy is identified in a child, peanut exposure should be avoided except when indicated by an allergist. Some children at high risk of peanut allergy may need an assessment for peanut allergy before they eat peanut for the first time.

For more information visit: Dietary exposures and allergy prevention in high-risk infants Learning Early About Peanut Allergy

MP: What is the treatment for existing food allergies?

JU: Currently the standard treatment for food allergies is to avoid the food and be prepared to treat reactions. There are many treatments being actively researched to see if they can provide alternatives. One type of treatment being researched is called food immunotherapy and it involves using controlled exposure to the allergic food by the skin, mouth or under the tongue to try to change the way the body reacts to the food. Food immunotherapy is not approved for use by Health Canada at this time. There are also other approaches for treatment at various stages of research in laboratories across the world. There is hope that there will be more options for food-allergic individuals in the future.